Current tomato peeling methods are of two general types: steam peeling and lye peeling.
In a current steam peeling process, tomatoes are subjected to pressurized steam to loosen the tomato peel. The advantage of a steam peeling process is that virtually all of the by-products of the process are edible and useable in the production of catsup and other consumables. Indeed, when the total output of the steam peeling process is assessed, including both whole tomatoes and by-products, fully 95% or more of the tomato input is recoverable. However, product throughput for any given commercially-available apparatus is generally limited to an established number of tons per hour, above which, peeling efficiency is minimized. For example, in a Food Machinery Corporation (FMC) Model SP-20 Tomato Steam Peeler, the generally-recognized upper limit of continuous throughput for an unmodified apparatus is approximately 23 to 24 tons per hour in peeling the “Brigade” tomato, a common tomato variety.
Further, the FMC SP-20 peels the Brigade tomato variety most efficiently at a temperature of approximately 300° F., and at a steam pressure of about 25 psi. However, it is expensive to generate high temperatures and steam pressures, and high temperatures and pressures degrade product quality (i.e. peel and fruit consistency and color, loss of nutritional constituents of the tomato) and reduce the number of whole tomatoes that may be recovered.
In a current lye peeling process, tomatoes are immersed in a solution of 15-20% lye at a temperature of about 180-200° F. for about 15-30 seconds. The lye-treated tomatoes are held for less than 3 minutes and the peel is slipped off of the underlying fruit. After the peel is removed, the whole tomato is washed, inspected, and used for canned or aseptic bulk tomato products. Using a lye peeling process, the whole-tomato product recovery is typically between 70% and 80% or less. However, lye is expensive and dangerous, and the reactivity of the lye limits the useful life of processing equipment. By-products of the lye peeling process are discarded as unusable and inedible waste, the tomato peel and other tomato by-products are also discarded, and valuable nutrients in the peel and byproduct such as carotenoids like lycopene and beta-carotene are lost.
Thus, it would be advantageous to peel tomatoes at lower temperatures while minimizing wasted by-product and maximizing product quality.